In recent years, a semiconductor detector of a photon counting type has been used for X-ray intensity measurement. In such a detector, each pixel (including a strip) has an individual characteristic, and difference in gain, behavior, or sensitivity is generated among pixels and individual variation appears even when each pixel is uniformly irradiated with a X-ray (refer to Patent Literature 1, for example).
Accordingly, an apparatus maker irradiates a detector with a uniform X-ray having a certain intensity before shipping a measurement apparatus, and thereby prepares a correction table to correct difference in a pixel gain or a count value among pixels (Flat-Field correction) according to a specific measurement condition, prepares a correction table to eliminate a bad pixel, or prepares a versatile table which can be used in some measurement conditions (refer to Patent Literatures 2 and 3, for example). FIG. 13 and FIG. 14 schematically show examples of the correction tables for the Flat-Field correction and correction for eliminating a bad pixel, respectively. Conventionally, a set of such correction tables is used for the correction.